require(ggplot);

print(ggraph::map("group", "paper"));
print(ggraph::map("group", type_a = "black", type_b = "red"));
print(ggraph::map("degree", [20, 100]));
print(ggraph::map("group", type_1 = 100, type_2 = 50, type_3 = 60, type_4 = 30));